Pointer instrument

ABSTRACT

There is provided a pointer type instrument which can reduce a light leakage to a side of a display board, and has a pointer  6  which includes an indication member  61  brightened by illumination light introduced from a back side of a rotation center region R and made of a translucent resin material, and a cover member  62  covering its outer periphery except for the back side of the rotation center region R and made of a light shielding resin material, and is driven to be rotated through a driving unit  2 ; a display board  3  which is disposed behind the pointer  6 , is apart from the cover member  62  with a predetermined gap part S intervening, and includes a light passing part  33  corresponding to the rotation center region R; and a light source  5  disposed behind the display board  3 , for generating the illumination light, wherein a leakage light prevention part  634  for suppressing a light leakage from the gap part S is provided on the back side (back side of a pedestal part  632 ) of the rotation center region R except for an introduction part (a light receiving part  611 , a reflection part  612 ) of the illumination light.

TECHNICAL FIELD

The present invention relates to a pointer type instrument adopted for,for example, an instrument for a vehicle, and particularly to a pointertype instrument of a type in which a pointer is brightened by lightingof a light source.

BACKGROUND OF INVENTION

Conventionally, a pointer type instrument is known in which a pointerfitted to a rotating shaft of a driving unit formed of, for example, astepping motor type or movable magnet type motor and interlocking withthe rotating shaft to be rotated above a display board, is constitutedby a translucent indication member including a light introduction partat a back side of a rotation center region, and illumination light of alight source disposed behind the display board is made incident on thelight introduction part of the indication member through a light passingpart of the display board, whereby the indication member (pointer) emitslight brightly.

In the pointer type instrument of this kind, since the rotation centerregion of the indication member is covered with a light shielding covermember in which its front and periphery presents a cap shape, a lightleakage from this part can be suppressed. However, the back side of therotation center region must be exposed to introduce the illuminationlight. Thus, there has been a case where the illumination light leaksinto a surrounding area from a gap part as a clearance between the covermember and the display board, this leakage light is reflected by thedisplay board to produce halation, and commodity quality is damaged.

From such circumstances, as disclosed in, for example, Japanese UtilityModel Publication No. 20097/1994 and as shown in FIG. 11, a pointer typeinstrument is proposed in which an annular light shielding ring C isprovided around a light passing part B made of a through hole of adisplay board A as a light introduction path of illumination light, andthis light shielding ring C is lapped over a cover member D, whereby theillumination light leaking into the outside from a gap part E issuppressed. Incidentally, in the drawing, reference character Fdesignates an indication member; G, a pedestal member (covering member)for fixing the indication member (pointer) F to a rotating shaft of adriving unit; H, a light guide body for guiding the illumination lightto the indication member F, F1, a light introduction part of theindication member F; and G1, an exposure part for exposing the lightintroduction part F1 and enabling the passing of the illumination light.

However, as described above, the conventional structure is such that thelight shielding ring C and the cover member D are lapped over each otherwhile a predetermined interval is provided, and the light leakage issuppressed, and there is a defect that in the illumination lighttraveling toward the side of the indication member F, the illuminationlight reflected by the back surface of the pedestal member G is apt toleak out from the gap portion E through a space between the lightshielding ring C and the cover member D, and in this point, there isroom for improvement.

The present invention has been made in view of this point, and has aprimary object to provide a pointer type instrument in which a lightleakage to the side of a display board is reduced and illuminationquality can be raised.

DISCLOSURE OF THE INVENTION

A pointer type instrument of the present invention comprises a pointerwhich includes an indication member made of a translucent resin materialand brightened by illumination light introduced from a back side of arotation center region, and a cover member covering its outer peripheryexcept for the back side of the rotation center region and made of alight shielding resin material, and is driven to be rotated through adriving unit formed of, for example, a stepping motor; a display boardwhich is disposed behind the pointer, is apart from the cover memberwith a gap part intervening, and includes a light passing partcorresponding to the rotation center region; and a light source disposedbehind the display board, for generating the illumination light, whereina leakage light prevention part for suppressing a light leakage from thegap part is provided on the back side of the rotation center regionexcept for an introduction part of the illumination light, whereby theillumination light traveling to the gap part can be reduced, the lightleakage to the outside (side of the display board) is effectivelysuppressed by this, and illumination quality can be raised.

The leakage light prevention part may be directly formed on the backsurface of the rotation center region of the indication member. In thecase where a covering member covering the back side of the rotationcenter region and provided with a transmission part enabling the passingof the illumination light is fitted to the pointer, the leakage lightprevention part can be formed on the back surface of the covering memberwhich becomes the introduction side of the illumination light.

As the leakage light prevention part, for example, a plurality ofprotrusions for blocking out the illumination light traveling toward theside of the gap part or an inclined surface for reflecting theillumination light to the side of the rotation center can be provided,and further, a crimped surface for diffusing the illumination light maybe provided, and an arbitrary structure can be selected as long as itcan reduce the illumination light traveling toward the gap part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 3 show a first embodiment of a pointer type instrumentaccording to the present invention, in which FIG. 1 is a front view ofthe pointer type instrument, FIG. 2 is a primary part sectional viewtaken along line A—A of FIG. 1, and FIG. 3 is a front view showing aback side of a pedestal member.

FIG. 4 is a sectional view showing a pedestal member according to asecond embodiment of the present invention.

FIG. 5 is a primary part sectional view showing a third embodiment ofthe present invention.

FIG. 6 is a primary part sectional view showing a fourth embodiment ofthe present invention.

FIG. 7 is a primary part sectional view showing a fifth embodiment ofthe present invention.

FIG. 8 is a primary part sectional view showing an eighth embodiment ofthe present invention.

FIG. 9 is a primary part sectional view showing a seventh embodiment ofthe present invention.

FIG. 10 is a primary part sectional view showing an eighth embodiment ofthe present invention.

FIG. 11 is a primary part sectional view showing a conventional example.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a first embodiment of the present invention will bedescribed with reference to FIGS. 1 to 3.

In FIGS. 1 and 2, a pointer type instrument is constituted by a drivingunit 1 formed of, for example, a stepping motor type electric motorincluding a rotating shaft 1, a display board 3 spaced a predeterminedinterval apart from the driving unit 2 and disposed on its front side, alight guide body 4 disposed behind this display board 3, a light source5, together with the light guide body 4, disposed behind the displayboard 3 and illuminating an after-mentioned pointer through the lightguide body 4, a pointer 6 interlocking with the rotating shaft 1 of thedriving unit 2 and rotating above the display board 3, and a collarmember 7 disposed between the pointer 6 and the display board 3.

In the display board 3, a ground color part 31 as a background and anindex part 32 as an indication object of the pointer 6 are formed byprinting on a thin plate base member made of a translucent syntheticresin, and in this case, a light shielding colored ink is used for theground color part 31, and a translucent colored ink is used for theindex part 32.

Besides, at a position of the display board 3 corresponding to anafter-mentioned rotation center region of the pointer 6, a light passingpart 33 made of a through hole is formed which enables coupling of thepointer 6 and the rotating shaft 1 and allows illumination light fromthe light source 5 to pass through. Incidentally, as long as theillumination light is allowed to pass through, the light passing part 33is not necessarily a throughhole but may be a transparent part or asemi-transparent part.

The light guide body 4 is made of a translucent synthetic resin materialprovided along the back surface of the display board 3, and asubstantially L-shaped bent part 41 extending to the side of the pointer6 across the light passing part 33 is formed at a place corresponding tothe light passing part 33 of the display board 3.

A tip part of this bent part 41 is formed as a light outgoing end part42 for irradiating the illumination light guided from the light source 5to the pointer 6, and a light guide body reflection part 43 forreflecting the illumination light to the side of the light outgoing endpart 42 is formed at a corner part corresponding to the light outgoingend part 42.

The pointer 6 is constituted by an indication member 61 made of atranslucent synthetic resin material, a cover member 62 covering apredetermined region of this indication member 61 and made of a lightshielding synthetic resin material, and a pedestal member (coveringmember) 63 for coupling the indication member 61 to the rotating shaft 1and made of a light shielding synthetic resin material. Incidentally,the entire or part of the pedestal member 63 can also be formed to betranslucent or semi-translucent.

The indication member 61 includes, in its rotation center region R, alight introduction part constituted by a light receiving part 611 forreceiving the illumination light irradiated from the light outgoing endpart 42 of the light guide body 4, and a reflection part 612 forreflecting the illumination light introduced from this light receivingpart 611 toward a longitudinal direction of the indication member 61 tolinearly brighten it.

The cover member 62 is formed into a cup shape opened at the back side(driving unit side) as the introduction side of the illumination light,includes a slit 621 for insertion of the indication member 61, and anopening end part 622 opposite to the board surface of the display board3 with a gap part S intervening, and covers the front and the peripheryof the indication member 61 except for its back side of the rotationcenter region R. Incidentally, an outer diameter of the cover member 62in a centrifugal direction is formed to be rather larger than an innerdiameter of the light passing part 33 of the display board 3.

The pedestal member 63 is constituted by a boss part 631 fixed to therotating shaft 1, and a disk-shaped pedestal part 632, and is integrallyfixed to the indication member 61 and the cover member 62 throughnot-shown fixing means.

In the pedestal part 632, a transmission part 633 for allowing theillumination light radiated from the light outgoing end part 42 of thelight guide body 4 to pass through to the side of the light receivingpart 611 is formed at a place corresponding to the light receiving part611 of the indication member 61. At the back side (introduction side ofthe illumination light) of the pedestal part 632 except for thetransmission part 633, a leakage light prevention part 634 is formedwhich reduces the illumination light traveling toward the clearance (gappart S) between the opening end part 622 of the cover member 62 and thedisplay board 3, and suppresses the light leakage from the gap part S.

The leakage light prevention part 634 is constituted by a plurality ofprotrusions protruding to the side of the light passing part 33 to bespaced a predetermined interval apart, and as shown in FIG. 3, therespective protrusions are formed as a plurality of peripheral wallssurrounding a rotation center (axial center of the rotating shaft 1) andhaving diameters gradually increasing in the direction from the rotationcenter to the outer periphery, and is constructed such that theseperipheral walls block out the illumination light traveling toward theside of the gap part S, and can suppress the light leakage from the gappart S.

As described above, in this embodiment, there are provided the pointer 6which includes the indication member 61 made of the translucent resinmaterial and brightened by the illumination light introduced from theback side of the rotation center region R, and the cover member 62covering its outer periphery except for the back side of the rotationcenter region R and made of the light shielding resin material, and isdriven to be rotated through the driving unit 2; the display board 3which is disposed behind the pointer 6, is apart from the cover member62 with the gap part S intervening, and includes the light passing part33 corresponding to the rotation center region R; and the light source 5disposed behind the display board 3, for generating the illuminationlight, and the leakage light prevention part 634 for suppressing thelight leakage from the gap part S is provided on the back side (backside of the pedestal part 632) of the rotation center region R exceptfor the introduction part (the light receiving part 611, the reflectionpart 612) of the illumination light, whereby the illumination lighttraveling to the gap part S can be reduced, the light leakage to theoutside (the side of the display board 3) is suppressed by this, and theillumination quality can be raised.

Besides, according to this embodiment, the leakage light prevention part634 is constituted by the plurality of protrusions which block off theillumination light traveling toward the side of the gap part S and haveconvex sectional shapes, and these protrusions are formed as theperipheral walls which surround the rotation center and have thediameters gradually increasing toward the outer periphery, whereby thelight leakage can be certainly suppressed over the whole area of therotation range of the pointer 6.

Incidentally, the sizes, formation pitch and formation number of theplurality of protrusions can be suitably set in accordance with requiredlight leakage suppression effects, specifications, and conditions,however, when a number of fine protrusions having small sizes and asmall formation pitch are formed, the thickness of the pedestal part 632can be made small while the light leakage suppression effect is raised,and this is advantageous for reducing the thickness of the pointer typeinstrument. Besides, in this embodiment, the collar member 7 is disposedbetween the pointer 6 and the display board 3, however, if a sufficientlight leakage suppression effect can be obtained by the leakage lightprevention part 634, it can be removed. As stated above, when the collarmember 7 is removed, the distance between the pointer 6 and the displayboard 3 can be made small and reduction in thickness becomes possible.

FIG. 4 is a sectional view showing a pedestal member (covering member)of a second embodiment of the present invention, which is the same asthat of the first embodiment except for the structure of a leakage lightprevention part 634.

That is, in this embodiment, a sectional shape of each of protrusions(leakage light prevention parts 634) formed at the back surface of apedestal part 632 of a pedestal member 63 is formed into a substantiallyserrate shape which has an apex T, and a long side L1 and a short sideL2 continuous with this apex T, and is tapered toward a tip. Thisembodiment is the same as the first embodiment in that the protrusionsformed into the substantially serrate shape form peripheral walls whichsurround the rotation center and have diameters gradually increasingtoward the outer periphery.

Besides, with respect to the long side L1 and the short side L2intersecting each other at the apex T, the long side L1 is positioned atthe side of the rotation center (inner side) and the short side L2 ispositioned at the outer side, and the long side L1 is formed to be aninclined surface facing to the side of the rotation center (side of arotating shaft 1) so that the illumination light impinging on this partis reflected to the side of the rotation center (inner side). On theother hand, the short side L2 extends substantially parallel to theaxial line of the rotating shaft 1.

As described above, in this embodiment, since the sectional shape of theprotrusion is formed into the substantially serrate shape, a plane partwhich is parallel to the board surface of the display board 3 and is aptto reflect the illumination light to the gap part S, can be lessened,and reflection of the illumination light to the side of the gap part Scan be more certainly reduced by this.

Besides, in this embodiment, the sectional shape of the protrusion isformed into the substantially serrate shape having the apex T, and thelong side L1 and the short side L2 continuous with the apex T, and atthis time, the long side L1 is formed of the inclined surface reflectingthe illumination light to the side of the rotation center, whereby thereflected light traveling to the side of the gap part S can be certainlyreduced.

FIGS. 5 to 7 are primary part sectional views showing modified examplesof the serrate protrusions, as third to fifth embodiments of the presentinvention, respectively, and in the third embodiment shown in FIG. 5, along side L1 and a short side L2 constituting a protrusion (leakagelight prevention part 634) are set to be curved surfaces. In the fourthembodiment shown in FIG. 6, respective sides L3 and L4 constituting aprotrusion are set to be plane surfaces equal to each other in length.Besides, in the fifth embodiment shown in FIG. 7, respective sides L3and L4 constituting a protrusion are set to be curved surfaces equal toeach other in length.

FIGS. 8 and 9 are primary part sectional views showing other structuresof a leakage light prevention part 634, as sixth and seventhembodiments. In the sixth embodiment shown in FIG. 8, a leakage lightprevention part 634 is positioned at the outer peripheral part of theback surface of a pedestal part 632, and is constituted by an inclinedsurface inclined to the side of the rotation center so that illuminationlight reaching this part is reflected to the side of the rotationcenter. In the seventh embodiment shown in FIG. 9, a leakage lightprevention part 634 is provided by inclining substantially the wholeback surface of a pedestal part 632 toward the side of the rotationcenter.

FIG. 10 is a primary part sectional view showing another structure of aleakage light prevention part of an eighth embodiment of the presentinvention, and in this embodiment, the back surface of a pedestal part632 is subjected to, for example, minute uneven working (crimp working)to provide a leakage light prevention part 634 formed of a crimpedsurface which diffuses and reflects the illumination light traveling tothis part, and reduces the light leakage from the gap part S.Incidentally, the leakage light prevention part 634 for diffusing andreflecting the illumination light in this way may be formed on the wholeregion of the back surface of the pedestal part 632 except for thetransmission part 633, or may be partially formed. Besides, the crimpedsurface may be combined with the inclined surfaces shown in FIGS. 8 and9 or the protrusion surface of the protrusion shown in FIG. 2.

Industrial Applicability

The present invention can be applied to not only the pointer typeinstrument for the vehicle, but also pointer type instruments mounted onall moving bodies, for example, a ship or an aircraft.

What is claimed is:
 1. A pointer type instrument comprising: a pointerwhich includes a translucent indication member brightened byillumination light introduced from a back side of a rotation centerregion, and a light shielding cover member covering its outer peripheryexcept for the back side of the rotation center region, and is driven tobe rotated through a predetermined driving unit; a display board whichis disposed behind the pointer, is apart from the cover member with agap part intervening, and includes a light passing part corresponding tothe rotation center region; and a light source disposed behind thedisplay board, for generating the illumination light, characterized inthat a leakage light prevention part for suppressing a light leakagefrom the gap part is provided on a back surface of the rotation centerregion except for an introduction part of the illumination light,wherein the leakage light prevention part includes a plurality ofprotrusions for blocking out the illumination light traveling toward aside of the gap part, and wherein the protrusions are formed asperipheral wall parts to protrude toward said light passing part and tosurround a rotation center.
 2. A pointer type instrument comprising: apointer which includes a translucent indication member brightened byillumination light introduced from a back side of a rotation centerregion, and a light shielding cover member covering its outer peripheryexcept for the back side of the rotation center region, and is driven tobe rotated through a predetermined driving unit; a display board whichis disposed behind the pointer, is apart from the cover member with agap part intervening, and includes a light passing part corresponding tothe rotation center region; a light source disposed behind the displayboard, for generating the illumination light; and a covering membercovering the back side of the rotation center region, characterized inthat a leakage light prevention part for suppressing a light leakagefrom the gap part is provided on a back surface of the covering memberas an introduction side of the illumination light, wherein the leakagelight prevention part includes a plurality of protrusions for blockingout the illumination light traveling toward a side of the gap part, andwherein the protrusions are formed as peripheral wall parts to protrudetoward said light passing part and to surround a rotation center.
 3. Apointer type instrument according to claim 2, wherein diameters of theperipheral wall parts gradually increase in a direction from therotation center to an outer periphery.
 4. A pointer type instrumentaccording to claim 2, wherein sectional shapes of the peripheral wallparts are substantially serrate.
 5. A pointer type instrument accordingto claim 4, wherein the sectional shape of each of the peripheral wallparts has an apex and a long side and a short side continuous with theapex, and the long side constitutes an inclined surface reflecting theillumination light to a rotation center side.